To increase the performance of a turbomachine, compressors, fans and turbines have seals. Seals made of abradable material are disposed on the surfaces of the stator and cooperate with the rotor. In particular, abradable seals are disposed on the inner surface of the casing of the low-pressure compressor and provide a sealing with the rotor blades of the compressor.
In order to lighten the casing of the compressor, it is known to manufacture the casing in a composite material with organic matrix and carbon fibers. However, the adhesion between the abradable material and the composite material of the casing is weak because of the differential expansion. To counter this effect, a metal strip is interposed between the casing and the abradable. The strip is bonded to the casing and its surface is perforated to improve the anchorage of the bonding material to the strip.
Patent document published EP 2 418 387 A1 discloses a composite casing of a compressor of an axial turbomachine. The casing includes a layer of abradable material with a metal strip or foil interposed between the abradable layer and the organic matrix composite casing. To improve the cohesion to the composite casing, the strip has a perforated surface.
However, these perforations weaken the abradable material in contact with the rotor blades of the compressor. In operation, due to repeated contacts between the rotor blades and the abradables, the latter shows a premature degradation and possibly a loss of cohesion. Therefore, the abradable seal no longer performs its function.